New contribution to the survey of the theory of the acrotony on the branch of one year grapevine: I - Investigation in the Tunisian vineyard

Research in the conduct mode of grapevines other than the north African goblet incited us to make an investigation on the no bursting on table vine canes and to study if the vestigial dormancy is equivalent to acrotony phenomenon. Results of this survey clearly show that this phenomenon varies from one year to the other and that there is a negative interrelationship between the percentage of buds no bursted and the diameter of the basis of the cane on the one hand and of the top on the other hand. The difference in diameters of the basis and apical part is weakly correlated with the percentage of buds no bursted. As a result we concluded that at the level of the cane, the percentage of buds no bursted doesn't only depend on the diameter of the cane but also on the fixing of this one on the carrier axis. The bibliographic survey puts in exergue the low temperature role. We tried to dissociate the acrotony phenomenon and the vestigial dormancy. Test result show that the long cane fixing at the temperature of 4°C during 10 days removes partially or completely the vestigial dormancy but the phenomenon of the acrotony persists. We examined the qualitative answers of the investigation. In Tunisia, on long canes of Muscatel of Italy, a certain percentage of one year old presents both the acrotony (80 p. cent) and the basitony phenomena (8 p. cent) in 1995. The discussion of results of the investigation allowed us to give out a new hypothesis of work concerning the phenomenon which we will to verify